Monitoring of dual-energy X-ray absorptiometry measurement in clinical practice

Short-Term Precision and Repeatability of Radiofrequency Echographic Multi Spectrometry (REMS) on Lumbar Spine and Proximal Femur: An In Vivo Study

To determine the short-term intra-operator precision and inter-operator repeatability of radiofrequency echographic multi-spectrometry (REMS) at the lumbar spine (LS) and proximal femur (FEM). All patients underwent an ultrasound scan of the LS and FEM. Both precision and repeatability, expressed as root-mean-square coefficient of variation (RMS-CV) and least significant change (LSC) were obtained using data from two consecutive REMS acquisitions by the same operator or two different operators, respectively. The precision was also assessed in the cohort stratified according to BMI classification. The mean (±SD) age of our subjects was 48.9 ± 6.8 for LS and 48.3 ± 6.1 for FEM. Precision was assessed on 42 subjects at LS and 37 subjects on FEM. Mean (±SD) BMI was 24.71 ± 4.2 for LS and 25.0 ± 4.84 for FEM. Respectively, the intra-operator precision error (RMS-CV) and LSC resulted in 0.47% and 1.29% at the spine and 0.32% and 0.89% at the proximal femur evaluation. The inter-operator variability investigated at the LS yielded an RMS-CV error of 0.55% and LSC of 1.52%, whereas for the FEM, the RMS-CV was 0.51% and the LSC was 1.40%. Similar values were found when subjects were divided into BMI subgroups. REMS technique provides a precise estimation of the US-BMD independent of subjects' BMI differences.

Dual-energy x-ray absorptiometry scanner mismatch in follow-up bone mineral density testing

Scanner mismatch occurs frequently with follow-up dual-energy x-ray absorptiometry (DXA) scans. Nearly one-in-five follow-up DXA scans were conducted on non-cross-calibrated scanners (scanner mismatch) and more than a quarter of patients who had a follow-up DXA scan had experienced scanner mismatch.

INTRODUCTION

Detecting significant changes in bone mineral density (BMD) with dual-energy x-ray absorptiometry (DXA) scanners relies on the least significant change (LSC). Results from two different DXA scanners can only be compared, albeit with decreased sensitivity for change, if the LSC between the two scanners has been directly determined through cross-calibration. Performing follow-up DXA scans on non-cross-calibrated scanners (scanner mismatch) has safety and economic implications. This study aims to determine the proportion of scanner mismatch occurring at a population level.

METHODS

All patients who completed at least two DXA scans between 1 April 2009 and 31 December 2018 in the province of Alberta, Canada, were identified using population-based health services databases. Scanner mismatch was defined as a follow-up DXA scan completed on a DXA scanner that differed from and was not cross-calibrated to the previous DXA scanner. Multivariate logistic regression models were used to assess predictive factors that may contribute to scanner mismatch.

RESULTS

A total of 264,866 patients with 470,641 follow-up DXA scans were identified. Scanner mismatch occurred in 18.9% of follow-up DXA scans; 28.7% of patients experienced at least one scanner mismatch. Longer duration between scans (OR 1.25, 95% CI 1.24-1.26) and major osteoporotic fracture history before index scan (OR 1.06, 95% CI 1.03-1.08) increased risk of scanner mismatch. Osteoporosis medication use before index scan (OR 0.89; 95% CI 0.88-0.91), recency of follow-up scans (OR 0.98, 95% CI 0.73-0.98), female sex (OR 0.97, 95% CI 0.94-1.00), and age at last scan (OR 0.99, 95% CI 0.99-1.00) were associated with lower risk of scanner mismatch.

CONCLUSION

Scanner mismatch is a common problem, occurring in one-in-five follow-up DXA scans and affecting more than a quarter of patients. Interventions to reduce this large proportion of scanner mismatch are necessary.

Evaluation of the bone mineral density in the Mexican female population using the Radiofrequency Echographic Multi Spectrometry (REMS) technology

The bone health status of a Mexican female population, including a cohort of 455 women aged over 40 years, was assessed by Radiofrequency Echographic Multi Spectrometry (REMS).

PURPOSE

Assessment of the bone health status in an average female Mexican population with REMS. The secondary objective investigated age- and body mass index (BMI)-related effects on the diagnostic classification and the influence of risk factors for osteoporosis.

METHODS

Women aged over 40 years underwent a REMS scan at the lumbar spine and both femoral necks. The degree of correlation of the bone mineral density (BMD) across axial sites was assessed by the Pearson correlation coefficient (r), along with the diagnostic discordance. The association between risk factors, age, and BMI and diagnostic classification was determined by the chi-squared test.

RESULTS

Four hundred seventy-one women were enrolled. Osteoporosis was diagnosed in 11.0%, 8.1%, and 8.3% of cases at the lumbar spine and right and left femoral neck, respectively. The diagnostic agreement between the lumbar spine and femoral necks was about 73% (85% considering a 0.3 T-score tolerance), whereas the agreement between the femoral necks was 97.4% (99.6% considering a 0.3 T-score tolerance). Most of discordant cases were minor discordances. The correlation between the lumbar spine and femoral neck was r = 0.82 and 0.85, respectively, whereas both femoral necks correlated with r = 0.97. As expected, the prevalence of osteoporosis increased with age and decreased as BMI increased.

CONCLUSION

The widespread applicability of the non-ionizing REMS technology has been demonstrated in a representative Mexican cohort, covering wide age and BMI ranges. Age and BMI variations correlate with the prevalence of osteoporosis, in line with the recent scientific literature.

The Effect of Resistance Training on Body Composition During and After Cancer Treatment: A Systematic Review and Meta-Analysis

BACKGROUND

Changes in body composition during cancer treatments have been linked with poorer outcomes, and increased morbidity and mortality. The effect of resistance training (RT) on body composition in cancer cohorts is debated.

OBJECTIVE

We conducted a systematic review and meta-analysis to determine the effect of RT on body composition during and after treatment.

METHODS

We searched five electronic databases for articles up to 1 February 2021 and included randomized controlled trials that compared RT with a non-exercise control in adults with cancer. Risk of bias was assessed using the RoB 2 tool. Pairwise, random-effects meta-analysis was used to synthesize the available data.

RESULTS

Overall, we included 15 studies (n = 1368). After treatment (11 studies), RT increased lean mass with moderate heterogeneity {0.41 kg [95% confidence interval (CI) 0.05, 0.76], p = 0.029; I² = 47.1%, p = 0.02} and decreased fat mass with substantial heterogeneity (- 0.59 kg [95% CI - 1.05, - 0.12], p = 0.019; I² = 69.1%, p < 0.001). During treatment (4 studies), RT did not increase lean mass (0.71 kg [95% CI - 0.04, 1.45], p = 0.05; I² = 0.0%, p = 0.75) or reduce fat mass (0.00 kg [95% CI - 5.31, 5.30], p = 0.99; I² = 0.0%, p = 0.62), both with no heterogeneity.

CONCLUSION

Modest improvements in body composition were observed following RT after cancer treatment; however, no changes were observed during treatment. These adaptations are markedly lower than those observed in healthy cohorts but may be clinically meaningful for the cancer survivorship population. At present it is unclear if these diminished adaptations are due to ineffective exercise prescriptions in cancer cohorts or due to an innate anabolic resistance as a result of cancer and its treatments.

STUDY REGISTRATION

Open Science Framework (osf.io/x6z72).

Operator-Related Errors and Pitfalls in Dual Energy X-Ray Absorptiometry: How to Recognize and Avoid Them

Dual-energy X-ray absorptiometry (DXA) is the most common modality for quantitative measurements of bone mineral density. Nevertheless, errors related to this exam are still very common, and may significantly impact on the final diagnosis and therapy. Operator-related errors may occur during each DXA step and can be related to wrong patient positioning, error in the acquisition process or in the scan analysis. The aim of this review is to provide a practical guide on how to recognize such errors in spine and hip DXA scan and how to avoid them, also presenting some of the most common artifacts encountered in clinical practice.

Assessing Periprosthetic Bone in Total Wrist Arthroplasty: The Validity of DXA

INTRODUCTION

Dual-energy X-ray absorptiometry (DXA) can measure bone mineral density (BMD) around joint arthroplasties. DXA has never been used in total wrist arthroplasties (TWA). We investigated (1) whether BMD differs between 2 TWAs implanted in the same cadaver forearm, (2) the effect of forearm rotation and wrist extension on measured BMD around TWA in a cadaver, and (3) the precision of DXA in a cadaver and patients.

METHODOLOGY

One ROI around the distal and 1 and 3 ROIs (ROI1-3) around the proximal component were used. Ten DXA scans were performed on forearm and femur mode convertible to orthopedic knee mode without arthroplasty, with ReMotion, and with Motec TWA in one cadaver forearm. Ten scans with 5° increments from 90°-70° pronation and 0°-20° extension, were performed with Motec. Precision was calculated as coefficient of variation (CV%) and least significant change (LSC%) from cadaver scans and double examinations with femur mode converted to orthopedic knee mode in 40 patients (20 ReMotion, 20 Motec).

RESULTS

BMD was higher in all Motec than corresponding ReMotion ROIs (p < 0.05). BMD changed with 10° supination in the distal ROI and ROI1, and with 5° extension in the distal ROI (p < 0.05). In the cadaver the orthopedic knee mode was more precise than the forearm mode in 3 Motec ROIs (p < 0.05). In patients CV was 2.21%-3.08% in the distal ROI, 1.66%-2.01% in the proximal ROI, and 1.98%-2.87% with 3 ROIs.

CONCLUSIONS

DXA is feasible for BMD measurement around the proximal component using the orthopedic knee mode, but not the distal component of TWA.

Short-Term Precision Error of Bone Strain Index, a New DXA-Based Finite Element Analysis Software for Assessing Hip Strength

Bone Strain Index (BSI) is a new finite element analysis tool applied to hip dual energy X-ray absorptiometry scans. The aim of this study was to assess the short-term precision error of BSI on the proximal femur, both on a phantom and patients. The International Society for Clinical Densitometry guidelines were followed for short-term precision error assessment. Dual energy X-ray absorptiometry measurements were performed on an anthropomorphic femur phantom that was scanned twice for 30 times, for a total of 60 scans. For the in vivo part, 30 subjects were scanned twice. BSI precision error was compared to that of bone mineral density (BMD). Both for the phantom and the in vivo study BSI reproducibility was lower compared to that of BMD, as the precision error of BSI resulted 3 times higher compared to that BMD. For phantom measurements, the highest precision value was that of total femur (TF) BMD (coefficient of variation [CoV] = 0.63%, reproducibility = 98.24%), while the lowest precision was the femoral neck (FN) BSI (CoV = 3.08%, reproducibility = 91.48%). Similarly, for the in vivo study, the highest precision was found at TF BMD (CoV = 1.36%, reproducibility = 96.22%), while the lowest value of precision was found for FN BSI (CoV = 4.17%, reproducibility = 88.46%). Reproducibility at TF was always better compared to that of the FN. BSI precision error was about 3 times higher compared to BMD, confirming previous results of lumbar spine BSI. The main source of variability of this new software is related to patient positioning.

Precision of Bone Mineral Density Measurements Around Total Ankle Replacement Using Dual Energy X-ray Absorptiometry

INTRODUCTION

Joint prosthesis survival is associated with the quality of surrounding bone. Dual-energy X-ray absorptiometry (DXA) is capable to evaluate areal bone mineral density (BMD) around different prosthetic implants, but no studies evaluated periprosthetic bone around total ankle replacement (TAR). Our aim is to determine the precision of the DXA periprosthetic BMD around TAR.

METHODOLOGY

Short-term precision was evaluated on 15 consecutive patients. Each ankle was scanned 3 times both in the posteroanterior (PA) and lateral views with a dedicated patient positioning protocol. Up to four squared regions of interest (ROIs) were placed in the periprosthetic bone around tibial and talar implants, with an additional ROI to include the calcaneal body in the lateral scan. Coefficient of variation (CV%) and least significant change were calculated according to the International Society for Clinical Densitometry.

RESULTS

The lateral projection showed lower mean CV values compared to the PA projection, with an average precision error of 2.21% (lateral scan) compared to 3.34% (PA scans). Overall, the lowest precision error was found at both "global" ROIs (CV = 1.25% on PA and CV = 1.3% on lateral). The highest CV value on PA was found at the medial aspect of talar side (ROI 3; CV = 4.89%), while on the lateral scan the highest CV value was found on the posterior aspect of talar side (ROI 2; CV = 2.99%).

CONCLUSIONS

We found very good reproducibility BMD values of periprosthetic bone around TAR, that were comparable or even better compared to other studies that evaluated periprosthetic BMD around different prosthetic implants. DXA can be used to precisely monitor bone density around ankle prostheses, despite further long-term longitudinal studies are required to assess the clinical utility of such measurements.

HR-pQCT Measures of Bone Microarchitecture Predict Fracture: Systematic Review and Meta-Analysis

High-resolution peripheral quantitative computed tomography (HR-pQCT) is a noninvasive imaging modality for assessing volumetric bone mineral density (vBMD) and microarchitecture of cancellous and cortical bone. The objective was to (1) assess fracture-associated differences in HR-pQCT bone parameters; and (2) to determine if HR-pQCT is sufficiently precise to reliably detect these differences in individuals. We systematically identified 40 studies that used HR-pQCT (39/40 used XtremeCT scanners) to assess 1291 to 3253 and 3389 to 10,687 individuals with and without fractures, respectively, ranging in age from 10.9 to 84.7 years with no comorbid conditions. Parameters describing radial and tibial bone density, microarchitecture, and strength were extracted and percentage differences between fracture and control subjects were estimated using a random effects meta-analysis. An additional meta-analysis of short-term in vivo reproducibility of bone parameters assessed by XtremeCT was conducted to determine whether fracture-associated differences exceeded the least significant change (LSC) required to discern measured differences from precision error. Radial and tibial HR-pQCT parameters, including failure load, were significantly altered in fracture subjects, with differences ranging from -2.6% (95% confidence interval [CI] -3.4 to -1.9) in radial cortical vBMD to -12.6% (95% CI -15.0 to -10.3) in radial trabecular vBMD. Fracture-associated differences reported by prospective studies were consistent with those from retrospective studies, indicating that HR-pQCT can predict incident fracture. Assessment of study quality, heterogeneity, and publication biases verified the validity of these findings. Finally, we demonstrated that fracture-associated deficits in total and trabecular vBMD and certain tibial cortical parameters can be reliably discerned from HR-pQCT-related precision error and can be used to detect fracture-associated differences in individual patients. Although differences in other HR-pQCT measures, including failure load, were significantly associated with fracture, improved reproducibility is needed to ensure reliable individual cross-sectional screening and longitudinal monitoring. In conclusion, our study supports the use of HR-pQCT in clinical fracture prediction. © 2019 American Society for Bone and Mineral Research.

Risk factors for bone loss in juvenile-onset systemic lupus erythematosus: a prospective study

OBJECTIVE

Juvenile-onset systemic lupus erythematosus (JoSLE) is associated with low bone mass for age and fractures; nevertheless, risk factors for bone impairment are poorly understood. The aim of this study was to evaluate risk factors for bone mass loss in JoSLE patients.

METHODS

Forty-nine female JoSLE patients were evaluated at baseline and after a 3.5-year follow-up regarding clinical, laboratory (including bone turnover markers), areal bone mineral density (aBMD) and bone microarchitecture parameters using high-resolution peripheral quantitative computed tomography (HR-pQCT). Based on the difference between final and baseline aBMD value, the patients were divided into three groups: aBMD gain (BG), aBMD loss (BL) and aBMD no change (NC).

RESULTS

The mean patient age was 18.7 ± 3.3 years. Sixty-one percent of patients presented with aBMD gain, 18.4% aBMD loss, and 20.4% remained stable during this follow-up period. Comparing the BL with the BG group, there was a higher frequency of alcohol consumption (p = 0.009), a higher frequency of inadequate calcium intake (p = 0.047) and lower levels of baseline procollagen type 1 amino-terminal propeptide (P1NP) (p = 0.036) in the BL group. Moreover, worsening of HR-pQCT parameters trabecular volumetric density (p = 0.003) and cortical thickness (p = 0.009) was observed in the BL group. In addition, a higher frequency of renal activity was observed comparing the BL + NC with the BG group (p = 0.036).

CONCLUSIONS

This is the first longitudinal study that has analyzed the risk factors of bone loss in JoSLE patients. The authors emphasize the importance of evaluating lifestyle habits and renal disease activity in these young women. Furthermore, this study suggests that trabecular and cortical compartments deteriorated, and low levels of P1NP may be a predictor of bone impairment in JoSLE.

Fat Mass Does Not Increase the Precision Error of Trabecular Bone Score Measurements

INTRODUCTION

Trabecular bone score (TBS) is an indirect index of trabecular microarchitecture derived from lumbar spine dual-energy X-ray absorptiometry. Previous phantom study showed that an increase in soft tissue thickness does not affect TBS reproducibility. We investigated the effect of increasing body mass index (BMI) and waist circumference on TBS precision error on patients, compared to bone mineral density (BMD).

METHODOLOGY

A population of postmenopausal Caucasian women was distributed in 3 different BMI (normal, overweight, and class I obesity), plus 2 further groups based on waist circumference diameter (≤88 cm and >88 cm, respectively). In vivo precision error was calculated on 30 consecutive subjects that were scanned 2 times, with patient repositioning, using the Hologic QDR-Discovery W densitometer. Coefficient of variation, percent least significant change, and reproducibility were calculated according to the International Society for Clinical Densitometry guidelines.

RESULTS

Ninety-five women aged 66 ± 10 (mean ± standard deviation) were included. No significant differences were found both for BMD and TBS precision errors, respectively, when comparing BMI groups and waist circumference groups. BMD reproducibility ranged from 95.9% (BMI > 30 kg/m²) to 97.5% (BMI < 25 kg/m²). TBS reproducibility ranged between 95.8% (BMI = 25-29.9 kg/m², waist circumference > 88 cm) and 96.6% (BMI < 25 kg/m²). With the exception of obese group, a significant difference was found between BMD and TBS reproducibility, being that of TBS slightly lower than BMD. A significant decrease of TBS values was found between normal and obese subjects, as well as between waist circumference groups.

CONCLUSIONS

TBS precision error is not affected by BMI and waist circumference differences. TBS reproducibility showed to be slightly lower than that of BMD, but this difference was mitigated in obese patients. A negative association was found between the amount of fat mass and TBS mean values.

Vitamin D status and abdominal aortic calcification in postmenopausal women

Vitamin D has an important role in bone metabolism and may be involved in the process of vascular calcification. The objective of this study was to evaluate the effect of vitamin D status on the presence of abdominal aortic calcification (AAC). We enrolled, in a cross-sectional study, 429 postmenopausal women [mean age, weight, and BMI of 59.5 ± 8.3 (50-83) years, 75.8 ± 13.3 (35-165) kg, and 29.9 ± 5.2 (14.6-50.8) kg/m², respectively]. Lateral vertebral fracture assessment (VFA) images and scans of the lumbar spine and proximal femur were obtained using a Lunar Prodigy densitometer. Vertebral fractures (VFs) were defined using the Genant semiquantitative (SQ) approach. We used the Kauppila score to assess AAC extension. Clinical risk factors of osteoporosis were collected, and 25-hydroxy vitamin D was measured using electrochemiluminescence (Roche). Prevalence of osteoporosis and hypovitaminosis D (<20 ng/ml) was 21.0% and 78.1%, respectively. VFs grade 2/3 were identified in 76 patients (17.7%). Two thirds of the evaluable participants did not have any detectable AAC. The prevalence of significant atherosclerotic burden, defined as a radiographic 24-point AAC score of 5 or higher, was 7.9%. The group of women with extended AAC were older and had a statistically significant higher menopause duration and more prevalent grade 2/3 VFs. Compared to women with normal values of vitamin D, women with vitamin D insufficiency (<20 ng/ml) and deficiency (<10 ng/ml) had a lower BMD and more prevalent VFs. No difference was noted with regard to AAC among the three groups. Multiple stepwise conditional logistic regression analysis showed that the presence of AAC was associated significantly with age and the presence of VFs. Extended aortic calcifications are independently associated with prevalent VFA-identified VFs but not with serum vitamin D levels in postmenopausal women. VFA imaging using DXA may detect at the same time prevalent VFs and AAC, an important cardiovascular disease risk factor.

Quality in dual-energy X-ray absorptiometry scans

Dual-energy X-ray absorptiometry (DXA) is the gold standard for measuring bone mineral density (BMD), making the diagnosis of osteoporosis, and for monitoring changes in BMD over time. DXA data are also used in the determination of fracture risk. Procedural steps in DXA scanning can be broken down into scan acquisition, analysis, interpretation, and reporting. Careful attention to quality control pertaining to these procedural steps should theoretically be beneficial in patient management. Inattention to procedural steps and errors that may occur at each step has the possibility of providing information that would inform inappropriate clinical decisions, generating unnecessary healthcare expenses and ultimately causing avoidable harm to patients. This article reviews errors in DXA scanning that affect trueness and precision related to the machine, the patient, and the technologist and reviews articles which document problems with DXA quality in clinical and research settings. An understanding of DXA errors is critical for DXA quality; programs such as certification of DXA technologists and interpreters help in assuring quality bone densitometry. As DXA errors are common, pay for performance requiring DXA technologists and interpreters to be certified and follow quality indicators is indicated.

An Advanced Quantitative Echosound Methodology for Femoral Neck Densitometry

The aim of this paper was to investigate the clinical feasibility and the accuracy in femoral neck densitometry of the Osteoporosis Score (O.S.), an ultrasound (US) parameter for osteoporosis diagnosis that has been recently introduced for lumbar spine applications. A total of 377 female patients (aged 61-70 y) underwent both a femoral dual X-ray absorptiometry (DXA) and an echographic scan of the proximal femur. Recruited patients were sub-divided into a reference database used for ultrasound spectral model construction and a study population for repeatability assessments and accuracy evaluations. Echographic images and radiofrequency signals were analyzed through a fully automatic algorithm that performed a series of combined spectral and statistical analyses, providing as a final output the O.S. value of the femoral neck. Assuming DXA as a gold standard reference, the accuracy of O.S.-based diagnoses resulted 94.7%, with k = 0.898 (p < 0.0001). Significant correlations were also found between O.S.-estimated bone mineral density and corresponding DXA values, with r(2) up to 0.79 and root mean square error = 5.9-7.4%. The reported accuracy levels, combined with the proven ease of use and very good measurement repeatability, provide the adopted method with a potential for clinical routine application in osteoporosis diagnosis.

Influence of obesity on vertebral fracture prevalence and vitamin D status in postmenopausal women

Background

It is well established that weight is an important determinant of bone health. Whereas obesity is associated with increased mortality and morbidity from diabetes and cardiovascular diseases, high body weight is widely believed to be associated to hypovitaminosis D and protective against the development of osteoporosis and fracture risk. The objective of the study was to evaluate the effect of BMI on vitamin D status and on densitometric vertebral fractures (VFs) in a large series of asymptomatic women aged over 50 who had a VFA examination during their bone mineral density (BMD) testing.

Methods

We enrolled 429 postmenopausal women (mean age, weight and BMI of 59.5 ± 8.3 (50 to 83) years, 75.8 ± 13.3 (35 to 165) kgs and 29.9 ± 5.2 (14.6 to 50.8) kg/m², respectively. Lateral VFA images and scans of the lumbar spine and proximal femur were obtained using a Lunar Prodigy densitometer. VFs were defined using the Genant semiquantitative (SQ) approach. Clinical risk factors of osteoporosis were collected and 25-hydroxivitamin D was measured using electrochimiluminescence (Roche).

Results

Prevalence of osteoporosis and hypovitaminosis D (<20 ng/ml) was 21.0 % and 78.1 % respectively. VFs grade 2/3were identified in 76 (17.7 %). Comparison between women according to their BMI showed that obese women had a higher BMD and less proportion of women with osteoporosis and VFs grade 2/3 than lean and overweight women. The prevalence of VFs globally increased with age and as BMI and BMD declined. Stepwise regression analysis showed that the presence of osteoporosis was independently related to BMI and history of fractures while the presence of grade 2/3 VFs was independently related to age, hypovitaminosis D and years of menopause.

Conclusion

Obese women had a higher BMD and lower prevalence of VFs. VFs were significantly related to age, hypovitaminosis D and years since menopause. However, among obese women, prevalence of VFs was increased in osteoporotic women.

Lower P1NP serum levels: a predictive marker of bone loss after 1 year follow-up in premenopausal systemic lupus erythematosus patients

SUMMARY

Predictors of bone mineral density (BMD) loss are additional tools in the management of osteoporosis in premenopausal women with systemic lupus erythematosus (SLE). This study provides original evidence that N-terminal propeptide of type 1 collagen (P1NP), the most specific bone formation marker, is a predictor of BMD loss in this group of women.

INTRODUCTION

SLE is associated with a high risk of low bone mass/fractures but this risk is still controversial in premenopausal women. Our aim was to determine the 1 year incidence of BMD loss in premenopausal SLE women and the value of bone turnover markers as predictors of this complication.

METHODS

This study enrolled a convenience sample of 63 premenopausal SLE patients. BMD was evaluated by dual X-ray absorptiometry at lumbar spine and hip at baseline and after 12 months. BMD changes above the least significant change were considered significant. Serum levels of P1NP and CTX (electrochemiluminescence), OPG, and RANKL (ELISA) were determined at baseline.

RESULTS

Mean age was 31.1±6.8 years, and disease duration was 5.25±3.8 years. 36.5 % of patients presented BMD loss and 17.5 % BMD gain at lumbar spine and/or hip. Patients were divided in three groups: BMD loss (BL), no BMD change (NC), and BMD gain (BG). Patients with BL and NC received similar cumulative/mean/maximum glucocorticoid doses during the study, but patients with BG received lower doses (p<0.05). Baseline P1NP levels were different in the groups (BL: 36.95±23.37 vs. NC: 54.63±30.82 vs. BG: 84.09±43.85 ng/mL; p=0.031 BL vs. NC, p<0.001 BL vs. BG, and p=0.039 NC vs. BG). There was no difference in CTX, OPG, or RANKL levels. After multivariate analysis, P1NP remained as an independent risk factor for BMD loss (p<0.03).

CONCLUSIONS

This study provides original evidence that lower levels of P1NP, the most specific bone formation marker, are predictive of BMD loss over 12 months in premenopausal SLE patients.

Osteoporosis, vertebral fractures and metabolic syndrome in postmenopausal women

BACKGROUND

The combined effect of the metabolic syndrome (MS) risk factors on bone health has led to controversial results and it is still not clear whether this effect is protective or detrimental. The study aimed to examine the association between MS and bone mineral density (BMD), osteoporosis, and vertebral fractures (VFs) among ambulatory older postmenopausal women.

METHODS

270 post-menopausal women with a mean age of 61.0 years ± 7.8 (50 to 90) with no prior known diagnosis of osteoporosis were recruited. BMD and Lateral vertebral fracture assessment (VFA) images were obtained using a GE Healthcare Lunar Prodigy densitometer. VFs were defined using a combination of Genant semiquantitative approach and morphometry.

RESULTS

The MS as defined by the NCEP-ATP III was present in 62 women (23.0%). According to the WHO classification, 82 had osteoporosis at any site (30.4%). VFs were identified in 116 (43.0%): 80 (29.6%) had grade 1 and 36 (13.3%) had grade 2 or 3. Women with MS had a significantly higher BMD and lower prevalence of osteoporosis (17.7% vs. 34.1%) than those without MS. No significant statistical difference was noted in prevalence of VFs (14.5 vs. 13.0%). There were significantly less women with MS among the group of osteoporotic women (13% vs. 27%; p = 0.018). Conditional regression binary analysis assessing the presence of osteoporosis as the dependent variable showed that women with a MS had a significant 71% decrease in the odds of being osteoporotic by BMD compared with women who had not MS accounting for age, BMI, number of parities and years since menopause.

CONCLUSION

Women with MS had higher BMD at the hip and spine, suggesting a protective effect of MS on bone. However, the prevalence of VFs was similar between women with or without MS.

Prevalence and type of errors in dual-energy x-ray absorptiometry

OBJECTIVES

Pitfalls in dual-energy x-ray absorptiometry (DXA) are common. Our aim was to assess rate and type of errors in DXA examinations/reports, evaluating a consecutive series of DXA images of patients examined elsewhere and later presenting to our institution for a follow-up DXA.

METHODS

After ethics committee approval, a radiologist retrospectively reviewed all DXA images provided by patients presenting at our institution for a new DXA. Errors were categorized as patient positioning (PP), data analysis (DA), artefacts and/or demographics.

RESULTS

Of 2,476 patients, 1,198 had no previous DXA, while 793 had a previous DXA performed in our institution. The remaining 485 (20 %) patients entered the study (38 men and 447 women; mean age ± standard deviation, 68 ± 9 years). Previous DXA examinations were performed at a total of 37 centres. Of 485 reports, 451 (93 %) had at least one error out of a total of 558 errors distributed as follows: 441 (79 %) were DA, 66 (12 %) PP, 39 (7 %) artefacts and 12 (2 %) demographics.

CONCLUSIONS

About 20 % of patients did not undergo DXA at the same institution as previously. More than 90 % of DXA presented at least one error, mainly of DA. International Society for Clinical Densitometry guidelines are very poorly adopted.

KEY POINTS

• More than 90 % of DXA examinations/reports presented one or more errors. • About 80 % of errors are related to image data analysis. • Errors in DXA examinations may have potential implications for patients' management.

The discriminative ability of FRAX, the WHO algorithm, to identify women with prevalent asymptomatic vertebral fractures: a cross-sectional study

BACKGROUND

A Moroccan model for the FRAX tool to determine the absolute risk of osteoporotic fracture at 10 years has been established recently. The study aimed to assess the discriminative capacity of FRAX in identifying women with prevalent asymptomatic vertebral fractures (VFs).

METHODS

We enrolled in this cross-sectional study 908 post-menopausal women with a mean age of 60.9 years ± 7.7 (50 to 91) with no prior known diagnosis of osteoporosis. Subjects were recruited from asymptomatic women selected from the general population. Lateral VFA images and scans of the lumbar spine and proximal femur were obtained using a GE Healthcare Lunar Prodigy densitometer. VFs were defined using a combination of Genantsemiquantitative (SQ) approach and morphometry. We calculated the absolute risk of major fracture and hip fracture with and without bone mineral density (BMD)using the FRAX website.The overall discriminative value of the different risk scores was assessed by calculating the areas under the ROC curve (AUC).

RESULTS

VFA images showed that 179 of the participants (19.7%) had at least one grade 2/3 VF. The group of women with VFs had a statistically significant higher FRAX scores for major and hip fractures with and without BMD, and lower weight, height, and lumbar spine and hip BMD and T-scores than those without a VFA-identified VF. The AUC ROC of FRAX for major fracture without BMD was 0.757 (CI 95%; 0.718-0.797) and 0.736 (CI 95%; 0.695-0.777) with BMD, being 0.756 (CI 95%; 0.716-0.796) and 0.747 (CI 95%; 0.709-0.785), respectively for FRAX hip fracture without and with BMD. The AUC ROC of lumbar spine T-score and femoral neck T-score were 0.660 (CI 95%; 0.611-0.708) and 0.707 (CI 95%; 0.664-0.751) respectively.

CONCLUSION

In asymptomatic post-menopausal women, the FRAX risk for major fracture without BMD had a better discriminative capacity in identifying the women with prevalent VFs than lumbar spine and femoral neck T-scores suggesting its usefulness in identifying women in whom VFA could be indicated.

In vivo precision of the GE lunar iDXA for the assessment of lumbar spine, total hip, femoral neck, and total body bone mineral density in severely obese patients

No study has evaluated the precision of the GE Lunar iDXATM (GE Healthcare) in measuring bone mineral density (BMD) among severely obese patients. The purpose of the study was to evaluate the precision of the GE Lunar iDXATM for assessing BMD, including the lumbar spine L1-L4, L2-L4, the total hip, femoral neck, and total body in a severely obese population (body mass index [BMI]>40 kg/m(2)). Sixty-four severely obese participants with a mean age of 46 ± 11 yr, BMI of 49 ± 6 kg/m(2), and a mean body mass of 136.8 ± 20.4 kg took part in this investigation. Two consecutive iDXA scans (with repositioning) of the total body (total body BMD [TBBMD]), lumbar spine (L1-L4 and L2-L4), total hip (total hip BMD [THBMD]), and femoral neck (femoral neck BMD [FNBMD]) were conducted for each participant. The coefficient of variation (CV), the root mean square (RMS) averages of standard deviations of repeated measurements, the corresponding 95% least significant change, and intraclass correlations (ICCs) were calculated. In addition, analysis of bias and coefficients of repeatability were calculated. The results showed a high level of precision for total body (TBBMD), lumbar spine (L1-L4), and total hip (THBMD) with values of RMS: 0.013, 0.014, and 0.011 g/cm(2); CV: 0.97%, 1.05%, and 0.99%, respectively. Precision error for the femoral neck was 2.34% (RMS: 0.025 g/cm(2)) but still represented high reproducibility. ICCs in all dual-energy X-ray absorptiometry measurements were 0.99 with FNBMD having the lowest at 0.98. Coefficients of repeatability for THBMD, FNBMD, L1-L4, L2-L4, and TBBMD were 0.0312, 0.0688, 0.0383, 0.0493, and 0.0312 g/cm(2), respectively. The Lunar iDXA demonstrated excellent precision for BMD measurements and is the first study to assess reproducibility of the GE Lunar iDXA with severely obese adults.

In vivo differences among scan modes in bone mineral density measurement at dual-energy X-ray absorptiometry

PURPOSE

Our aim was to estimate the in vivo reproducibility of bone mineral density (BMD) at dual-energy X-ray absorptiometry (DXA) and to compare fast array, array, and high-definition scan modes.

MATERIALS AND METHODS

A total of 378 patients (38 males and 340 females; mean age 63 ± 9 years) underwent DXA using a QDR-Discovery A densitometer (Hologic). Considering the three scan modes on lumbar spine and right femur, six independent groups of 30 patients were examined twice (for a total of 180 patients). Least significant change (LSC) and smallest detectable difference (SDD) were calculated. The remaining 198 patients underwent three scans of the lumbar spine (n = 92) or of the right femur (n = 106), one for each scan mode. The student t test and Bland-Altman analysis used were. Scan times were recorded and radiation dose was estimated using the ICRP60 method.

RESULTS

Intra-scan mode reproducibility was 98-99%, corresponding to an LSC of 1.49-2.08%. The SDD was 0.018-0.023 g/cm(2) (lumbar spine) and 0.017-0.019 g/cm(2) (right femur). All comparisons among scan modes were statistically significant (p < 0.001) but lower than SDDs, i.e. not clinically relevant. Considering lumbar spine and the right femur, scan times were 50 and 38 s for fast array, 98 and 74 s for array, and 195 and 148 s for high definition, respectively; radiation doses were 6.7 and 4.7 μSv for fast array, and 13.3 and 9.3 μSv for both array and high definition, respectively.

CONCLUSION

Since all BMD differences were lower than the SSDs, the three scan modes can be considered interchangeable. As a consequence, although the absolute reduction in time and radiation dose is relatively low, when BMD measurement is the aim of DXA, fast array can be generally preferred.

Osteoporosis update from the 2012 Santa Fe Bone Symposium

The core of the 2012 Santa Fe Bone Symposium consisted of plenary presentations on new developments in the fields of osteoporosis and metabolic bone disease, with a focus on current and future implications for patient care. These were complemented by oral abstracts, interactive discussions of challenging cases, a debate on benefits and risks of long-term bisphosphonate therapy, and a panel discussion of controversial issues in the management of osteoporosis. Other topics included a review of the most important scientific publications in the past year, new and emerging therapy for osteoporosis, the benefits and limitations of clinical practice guidelines in the care of individual patients, the effects of metallic elements on skeletal health, clinical applications of bone turnover markers, an engineering perspective of skeletal health and disease, and an update on the role of the International Society for Clinical Densitometry in education, certification, accreditation, and advocacy for high-quality bone density testing. The symposium was highlighted by an inaugural presentation of "2 Million 2 Many," a national campaign of the National Bone Health Alliance to increase awareness of osteoporosis.

Vertebral fractures and abdominal aortic calcification in postmenopausal women. A cohort study

INTRODUCTION

Vertebral fracture assessment (VFA) imaging with a bone densitometer can simultaneously detect prevalent vertebral fractures (VFs) and abdominal aortic calcification (AAC).

OBJECTIVE

To study the relation between the prevalence of VFs using VFA in asymptomatic women and the prevalence and severity of AAC.

DESIGN

This is a cross-sectional study.

SETTINGS

Subjects were recruited in a third care center from asymptomatic women selected from the general population.

PARTICIPANTS

We enrolled 908 post-menopausal women with a mean age of 60.9 years ± 7.7 (50 to 91) with no prior known diagnosis of osteoporosis or taking medication interfering with bone metabolism.

PRIMARY AND SECONDARY OUTCOME MEASURES

Lateral VFA images and scans of the lumbar spine and proximal femur were obtained using a GE Healthcare Lunar Prodigy densitometer. VFs were defined using a combination of Genant semiquantitative (SQ) approach and morphometry. VFA images were scored for AAC using a validated 24 point scale.

RESULTS

VFA images showed that 179 of the participants (19.7%) had at least one grade 2/3 VF, 81% did not have any detectable AAC whereas the prevalence of significant atherosclerotic burden, defined as AAC score of 5 or higher, was 12%. The group of women with 2/3 VFs had a statistically significant higher AAC score and higher proportion of subjects with extended AAC, and lower weight, height, and lumbar spine and hip BMD and T-scores than those without VFA-identified VFs. Multiple regression analysis showed that the presence of grade 2/3 VFs was significantly associated with age, BMI, history of peripheral fracture, AAC score ≥ 5 and densitometric osteoporosis.

CONCLUSION

In post-menopausal women, extended AAC is independently associated with prevalent VFs regardless of age, BMI, history of fractures, and BMD.

Relationship of bone mineral density to progression of knee osteoarthritis

OBJECTIVE

To evaluate the longitudinal relationship between bone mineral density (BMD) and BMD changes and the progression of knee osteoarthritis (OA), as measured by cartilage outcomes.

METHODS

We used observational cohort data from the Vitamin D for Knee Osteoarthritis trial. Bilateral femoral neck BMD values as well as knee magnetic resonance imaging (MRI) scans in each subject were obtained at baseline and subsequently at 12 months and 24 months. The change in total cartilage volume and tibial and femoral cartilage thickness was measured by manual cartilage segmentation of 2 sequential knee MRI scans in each subject. Multivariable linear regression models were used to examine the associations of baseline BMD and BMD change with the cartilage outcomes, adjusting for baseline age, sex, body mass index, malalignment, and vitamin D treatment. Model fit and assumptions were validated.

RESULTS

A total of 127 subjects were eligible for analysis. Longitudinal BMD loss was associated with loss of cartilage volume (β = 1.25 per 0.1 gm/cm(2) , P = 0.02) and loss of tibial cartilage thickness (β = 0.028, P = 0.03). BMD loss of a magnitude greater than the least significant change (<-4.7%) was associated with 1.02% cartilage volume loss per year (P = 0.005), 0.014 mm femoral cartilage thickness loss (P = 0.04), and 0.021 mm tibial cartilage thickness loss per year (P = 0.009). There were no significant associations between baseline BMD and any of the cartilage outcomes.

CONCLUSION

Longitudinal BMD loss is associated with progressive cartilage loss in knees with OA. Further work to clarify the basis of this relationship could reveal novel therapeutic targets for knee OA.

Use of dual X-ray absorptiometry to measure body mass during short- to medium-term trials of nutrition and exercise interventions

Dual X-ray absorptiometry (DXA) has a range of clinical applications, from assessing associations between adipose or lean body mass and the risk of disease to measuring the effects of dietary interventions on adipose deposition and oxidation and/or muscle accumulation. Many lifestyle-related studies, however, are short- to medium-term interventions, and inter- or intradevice variation between DXA scanners can facilitate type I and type II errors during data analysis. Studies demonstrate that variation in body composition measurements exist not only between DXA instruments using fan-beam and pencil-beam technologies but also between DXA instruments produced by different manufacturers. Moreover, studies show inter- and intrainstrument variation between identical DXA instruments. Such inter- and intrascan variability between instruments can be compounded by the particular patient population being investigated. The objective of this review is to discuss inter- and intradevice variation of DXA instruments and to outline quality control procedures that should be implemented prior to initiating short-term single or multicenter clinical trials that use DXA to investigate the effects of an intervention on loss or accretion of lean or fat mass.

Systematic vertebral fracture assessment in asymptomatic postmenopausal women

INTRODUCTION

Recognition of vertebral fractures (VFs) changes the patient's diagnostic classification, estimation of fracture risk, and threshold for pharmacological intervention. Vertebral fracture assessment (VFA) enables the detection of VFs in the same session as bone mineral density (BMD) testing.

OBJECTIVE

To study prevalence and risk factors of VFs using VFA in asymptomatic women and measure its effect on treatment recommendations.

METHODS

We enrolled 908 postmenopausal women (mean age, weight and BMI of 60.9 ± 7.7 (50-91) years, 73.2 ± 13.2 (35-150) kg and 29.8 ± 5.3 (14.5-50.8) kg/m(2), respectively. Lateral VFA images and scans of the lumbar spine and proximal femur were obtained using a GE Healthcare Lunar Prodigy densitometer. VFs were defined using a combination of Genant semiquantitative (SQ) approach and morphometry.

RESULTS

VFs were identified in 382 patients (42.0%): 203 (22.3%) had grade 1 and 179 (19.7%) had grade 2 or 3. The prevalence of VFA-detected fractures globally increased significantly with age and as BMI and BMD declined. A fracture was identified on VFA in 63 (28.3%) women with normal BMD (8.5% had grade 2/3 VFs) and in 145 (38.5%) with osteopenia (15.7% had grade 2/3 VFs). Stepwise regression analysis showed that presence of VFs was independently related to age, BMI, number of parity, history of peripheral fracture and lumbar spine BMD.

CONCLUSION

A high proportion of women with asymptomatic VFs would not receive treatment if screening were based only on BMD evaluation. Our results support the recommendation to enlarge the indications of VFA in the presence of risk factors such as age over 60, multiparity, history of peripheral traumatic fractures and low BMI.

Prevalence and Risk Factors of Discordance between Left- and Right-Hip Bone Mineral Density Using DXA

To determine the prevalence of significant left-right differences in hip bone mineral density (BMD), and the impact of this difference on osteoporosis diagnosis, we measured bilateral proximal femora using dual energy X-ray absorptiometry (DXA) in 3481 subjects (608 males, 2873 females). The difference between left and right hip was considered significant if it exceeded the smallest detectable difference (SDD) for any of the three hip subregions. Contralateral femoral BMD was highly correlated at all measuring sites (r = 0.92-0.95). However, significant left-right differences in BMD were common: the difference exceeded the SDD for 54% of patients at total hip, 52.1% at femoral neck, and 57.7% at trochanter. The prevalence of left-right differences was greater in participants >65 years. For 1169 participants with normal spines, 22 (1.9%) had discordant left-right hips in which one hip was osteoporotic; for 1349 patients with osteopenic spines, 94 (7%) had osteoporosis in one hip. Participants with BMI < 20 kg/m(2) were more likely to show major T-score discordance (osteoporosis in one hip and normal BMD in the other). Multiple regression analysis showed that the only significant statically parameter that persists after adjusting for all potential confounding parameters were age over 65 years.

Relationship between vertebral fracture prevalence and abdominal aortic calcification in men

OBJECTIVE

To study the relationship between the prevalence of vertebral fractures (VFs) using VF assessment (VFA) in asymptomatic men and the prevalence and severity of abdominal aortic calcification (AAC).

METHODS

We enrolled 709 men with mean (s.d.) age 62.4 (8.6) (range 45-89) years. Lateral VFA images and scans of the lumbar spine and proximal femur were obtained using a GE Healthcare Lunar Prodigy densitometer. VFs were defined using a combination of the Genant semi-quantitative (SQ) approach and morphometry. VFA images were scored for AAC using a validated 24-point scale.

RESULTS

VFA images showed that 68 (14.2%) of the participants had at least one grade 2/3 VF, 82% did not have any detectable AAC, whereas the prevalence of significant atherosclerotic burden, defined as an AAC score of ≥5, was 2.8%. The group of men with grade 2/3 VFs had a statistically significant higher AAC score and higher proportion of subjects with extended AAC, and lower weight, height and lumbar spine and hip BMD and T-scores than those without a VFA-identified VF. Multiple regression analysis showed that the presence of grade 2/3 VFs was significantly associated with BMI [odds ratio (OR 0.915; 95% CI 0.589, 0.975; P = 0.006], AAC score ≥5 (OR 4.509; 95% CI 1.505, 13.504; P = 0.007) and osteoporosis in any site (OR 5.159; 95% CI 3.116, 8.540; P ≤ 0.0001).

CONCLUSION

In elderly men, extended AAC is an indicator of the increased risk for prevalent VFs regardless of age, BMI, history of fractures, smoking and BMD.

Hypovitaminosis D and prevalent asymptomatic vertebral fractures in Moroccan postmenopausal women

BACKGROUND

Hypovitaminosis D is associated to accentuated bone loss. However, association between osteoporotic vertebral fractures (VFs) and vitamin D status has not been clearly established.

OBJECTIVE

To determine serum vitamin D status and to assess the association of vitamin D status with bone mineral density (BMD) and asymptomatic VFs prevalence using vertebral fracture assessment (VFA) in a cohort of Moroccan menopausal women.

METHODS

from June to September 2010, 178 menopausal women 50 years old and over were enrolled in this cross-sectional study. The mean ± SD (range) age, weight, height and BMI were 58.8 ± 8.2 (50 to 79) years, 73.2 ± 13.8 (35 to 119) Kgs, 1.56 ± 0.06 (1.43 - 1.79) m and 29.8 ± 5.9 (17.5 - 49.8) kg/m2, respectively. VFA images and scans of the lumbar spine and proximal femur were obtained using a GE Healthcare Lunar Prodigy densitometer. VFs were defined using a combination of Genant semiquantitative approach and morphometry. Serum levels of 25-hydroxyvitamin D (25(OH)D) were measured.

RESULTS

Among the 178 women, 45 (25.2%) had densitometric osteoporosis, and on VFA, VFs (grade 2 or 3) were detected in 20.2% while grade 1 were identified in 33.1%. The mean values of serum levels of 25(OH)D were 15.8 ± 11.6 ng/ml (range: 3.0 - 49.1) with 152 patients (85.3%) having levels <30 ng/ml (insufficiency) and 92 (51.6%) <10 ng/ml (deficiency). Stepwise regression analysis showed that presence of VFs was independently related to age, 25(OH)D and densitometric osteoporosis.

CONCLUSION

our study shows that advanced age, hypovitaminosis D and osteoporosis are independent risk factors for asymptomatic VFs in Moroccan postmenopausal women.

Vertebral fracture assessment in asymptomatic men and its impact on management

INTRODUCTION

Recognition of vertebral fractures (VFs) change the patient's diagnostic classification, estimation of fracture risk, and threshold for pharmacological intervention. Vertebral fracture assessment (VFA) enables the detection of VFs in the same session as bone mineral density (BMD) testing.

OBJECTIVE

To study prevalence and risk factors of VFs using VFA in asymptomatic men and measure its impact on patients' management.

METHODS

We enrolled 791 men aged between 45 and 89 (mean age, weight and BMI of 62.4±8.6) (45 to 89) years, 74.9±12.7 (40 to 163) and 26.3±4.0 (16.6 to 43.8) kg/m(2), respectively. Lateral VFA images and scans of the lumbar spine and proximal femur were obtained using a GE Healthcare Lunar Prodigy densitometer. VFs were defined using a combination of Genant semiquantitative (SQ) approach and morphometry.

RESULTS

VFs were identified in 318 (40.3%): 206 (26.0%) had grade 1 and 112 (14.2%) had grade 2 or 3. As would be expected, the prevalence of VFA-detected fractures globally increased significantly with age and as BMI and BMD declined. A fracture was identified on VFA in 85 (32.4%) of men with normal BMD (6.9% had grade 2/3 VFs) and in 144 (35.8%) with osteopenia (11.7% had grade 2/3 VFs). Stepwise regression analysis showed that presence of VFs was independently related to the osteoporotic status (OR=4.761, 95%CI [2.956-7.668]; p<0.0001) and current smoking (OR=1.717, 95%CI [1.268-2.323]; p=0.002).

CONCLUSION

Our results support the recommendation to enlarge the indications of VFA to all the men referred for DXA measurement.

Prevalence and risk factors of osteoporosis and vertebral fractures in patients with ankylosing spondylitis

Ankylosing spondylitis (AS) is characterized by inflammation of the entheses and paravertebral structures, leading in time to bone formation at those sites. As well, vertebral bone loss is also a recognized feature of AS Objective: To calculate the prevalence and risk factors of osteoporosis and vertebral fractures in patients with AS.

METHODS

Eighty patients with AS were enrolled in the study. Clinical, biological and radiological status was assessed by the Bath AS Disease Activity Index (BASDAI), Bath AS Functional Index (BASFI), ESR and C-reactive protein (CRP), Bath AS Radiology Index (BASRI) and modified stoke AS spine score (mSASSS). BMD of the hip and spine was measured and vertebral fractures were defined using a combination of Genant semiquantitative (SQ) approach and morphometry by VFA (fracture vertebral assessment).

RESULTS

The years+/-11.8. The mean BMI was 22.8 kg/m(2)+/-4.1 and the mean disease duration was 10.8 years+/-6.6. Prevalence of osteoporosis was 25%. 18.8% of patients had a vertebral fracture (grades 2 and 3). Factors associated with osteoporosis were low weight and BMI and longer disease duration, higher ESR, CRP, BASFI and BASDAI. Vertebral fractures were associated with advanced age, longer disease duration, higher BASFI, BASRI and mSASSS and reduced BMD and T-score at the hip site, presence of osteoporosis at any site. Multiple logistic regression analysis (Table 4) revealed that parameters significantly associated with osteoporosis were BASDAI (OR=1.05, 95% confidence interval [CI]: 1.03-1.09); disease duration (OR=1.13, 95%CI: 1.03-1.25); and BMI (OR=0.82, 95%CI: 0.69-0.93). The presence of VFs (grades 2 and 3) were independently associated with disease duration (OR=1.50, 95%CI: 1.07-2.10); and mSASSS (OR=1.17, 95%CI: 1.05-1.30).

CONCLUSION

Osteoporosis is common in patients with AS and seems to be related to disease activity while vertebral fractures appear to be related to the duration and structural severity of the disease rather than BMD.

Vertebral fracture assessment in healthy men: prevalence and risk factors

INTRODUCTION

Vertebral fracture assessment (VFA) is a technology that can reliably and accurately diagnose vertebral fractures with greater patient convenience, less radiation exposure, and lower cost than standard spine radiography.

OBJECTIVE

To study prevalence and risk factors of vertebral fractures using VFA in healthy men.

METHODS

The study cohort consists of a population of 216 healthy men aged between 50 and 79 (mean age, weight and BMI of 63.8 years, 73.3 kg and 25.7 kg/m2, respectively). Lateral VFA images and scans of the lumbar spine and proximal femur were obtained by two technologists using a GE Healthcare Lunar Prodigy densitometer. Vertebral fractures were defined using a combination of Genant semiquantitative (SQ) approach and morphometry.

RESULTS

Ninety-three percent of vertebrae from T4-L4 and 98% from T8-L4 were adequately visualized on VFA. Vertebral fractures were detected in 29.6% (64/216) of these men: 34/216 (15.7%) had grade 1 and 30/216 (13.8%) had grades 2 or 3. Twenty one of men with VFA-identified fracture (32.8%) had only a single vertebral fracture, while the other 67.2% had two or more. Fractures were most common in the mid-thoracic spine and at the thoraco-lumbar junction. As would be expected, the prevalence of VFA-detected fractures increased with age and as BMD declined. This group of men had a statistically significant lower weight, height, calcium consumption and T-score than those without a VFA-identified vertebral fracture. Regression analysis showed that presence of vertebral fracture was mainly related to the osteoporotic status (OR: 9.0; 95% CI: 3.5-22.8).

CONCLUSION

VFA allows evaluation of the majority of vertebral bodies in men. Vertebral fractures are common in healthy men and are related to low BMD.

DXA scanning in clinical practice

Dual-energy X-ray absorptiometry (DXA) is recognized as the reference method to measure bone mineral density (BMD) with acceptable accuracy errors and good precision and reproducibility. The World Health Organization (WHO) has established DXA as the best densitometric technique for assessing BMD in postmenopausal women and based the definitions of osteopenia and osteoporosis on its results. DXA allows accurate diagnosis of osteoporosis, estimation of fracture risk and monitoring of patients undergoing treatment. However, when DXA studies are performed incorrectly, it can lead to major mistakes in diagnosis and therapy. This article reviews the fundamentals of positioning, scan analysis and interpretation of DXA in clinical practice.

Prevalence and risk factors of osteoporosis in patients with Parkinson's disease

Parkinson's disease (PD) is the most common cause of disability in the elderly. It is currently recognized as a cause of secondary osteoporosis. To evaluate the prevalence of osteoporosis in PD and detect its risk factors, 52 patients with PD (36 men/16 women) and 52 controls paired for age and sex were recruited. Clinical data including demography, disease duration and disease severity were collected. All subjects had bone mineral density (BMD) measured by dual energy X-ray absorptiometry, dorsal and lumbar spine X-ray, and biological exams (osteocalcin, CTX, parathormon). The mean age of the patients was 60.0 +/- 9.25 years [30-77], and the mean disease duration was 4.9 +/- 4.5 years [0.2-17]. Nine patients (17.3%) were osteoporotic and 28 (53.8%) osteopenic. BMD at the lumbar spine and the hip was lower among patients than controls (spine: 1.031 vs. 1.175 g/cm(2); P < 0.001; hip: 0.968 vs. 1.054; P = 0.02). PD patients with low BMD presented a more severe disease and an insufficient sun exposure and calcium intake. There was a positive statistically significant correlation between patients BMD and body mass index and negative correlation with age, severity of PD, and osteocalcin levels. The prevalence of osteoporosis/osteopenia is high in PD patients and seems related to the severity of the disease, an insufficient sun exposure and calcium intake. This osteoporosis constitutes with falls the major risk factors of fracture in PD patients.

Primary biliary cirrhosis and osteoporosis: a case-control study

Osteoporosis is a common complication of chronic liver disease, from cholestatic disorders to autoimmune, alcoholic, and posthepatitic cirrhosis. Osteoporosis appears more striking in patients with primary biliary cirrhosis (PBC) because the disease usually affects elderly women, who are naturally prone to osteoporosis. Our aims were (1) to compare the prevalence of osteoporosis (T-score <-2.5 SD) between PBC patients and a group of age-and sex-matched controls consisting of healthy subjects from the general population; and (2) to identify the main risk factors for the development of bone loss. Thirty-three women with PBC (mean age, 47.3 +/- 10.4 years) and 66 healthy subjects were enrolled in the study. Bone mineral density (BMD) was assessed at the lumbar spine by dual-photon X-ray absorptiometry. Bone metabolism was evaluated by measuring serum calcium corrected for serum albumin, 25-hydroxyvitamin D (25-OH vit D), parathyroid hormone, and osteocalcin. Vertebral fractures were analyzed using vertebral fracture assessment (VFA). The mean T-score was lower in the PBC group compared to healthy controls, with a significant statistical difference (-2.39 +/- 0.93 and -1.47 +/- 0.99 in lumbar spine and total hip, respectively, in the PBC group versus -0.99 +/- 0.51 and -0.56 +/- 1.14 in healthy controls (P < 0.001). The prevalence of osteoporosis was 51.5% in the PBC group versus 22.7% in healthy controls with a statistically significant difference (P = 0.004). BMD of the PBC group was significantly correlated positively with body mass index (BMI) and 25-OH vit D, and negatively with menopausal status, duration of disease, and parathyroid hormone (PTH) levels. Vertebral fractures were present in 9% of the patients. We found that osteoporosis is more prevalent in women with PBC than in the general population. BMI, menopausal status, duration of the disease, and vitamin D deficiency are the main risk factors for osteoporosis in this liver disease.

Performance of the osteoporosis risk assessment tool in Moroccan men

Measuring bone mineral density (BMD) is a widely accepted strategy for identifying subjects with an increased risk of fracture. However, because of limited availability of BMD technology in some communities and cost considerations, it has been proposed that BMD measurements be targeted to subjects with risk factors for osteoporosis. Osteoporosis self-assessment tool (OST) using age and weight have been developed to identify women who are more likely to have low BMD and thus undergo BMD testing. To study the performance of OST in identifying osteoporotic white men in Morocco. We analysed in an epidemiological cross-sectional study the records for 229 white Moroccan men seen at an out-patient rheumatology centre. OST was compared to bone density T scores and the ability of OST to identify men with osteoporosis (T < -2.5) was evaluated. Using an OST score < 2 to recommend dual X-ray absorptiometry (DXA) referral, sensitivity ranged from 63% at the lumbar spine to 87% at the total hip to detect BMD T scores of -2.5 and specificity from 58 to 59%. The negative predictive value was high at all skeletal sites (87-98%), demonstrating the usefulness of the OST to identify patients who have normal BMD and should not receive DXA testing. The performance of OST among men in Morocco was similar to that reported earlier for the other samples in Asian countries and the USA. The OST is an effective and efficient tool to help target high-risk men for DXA measurement.

Discordance in diagnosis of osteoporosis using spine and hip bone densitometry

Diagnostic discordance for osteoporosis is the observation that the T-score of a patient varies between skeletal sites, falling into 2 different diagnostic categories identified by the World Health Organization classification system. Densitometrists and clinicians should expect that at least 4 of every 10 patients tested by dual-energy X-ray absorptiometry (DXA) to demonstrate T-score discordance between spine and total hip measurement sites. T-score discordance can occur for a variety of reasons related to physiologic and pathologic patient factors and the performance or analysis of DXA itself.

Body mass index and gynecological factors as determinants of bone mass in healthy Moroccan women

Several studies have shown that low body mass index (BMI) is associated with low BMD and fractures. However, the results that have been published from studies on reproductive factors and BMD are extremely controversial, with some demonstrating a beneficial effect, while others show a detrimental impact of these factors on bone mass.

OBJECTIVE

To study the influence of several gynecological factors (years since menopause (YSM), age at menarche and gynecological age or reproductive life) simultaneously with anthropometric factors as determinants of bone mineral density (BMD) in healthy women older than 40.

METHODS

BMD was determined by dual energy X-ray absorptiometry (DXA) at the lumbar spine and femurs in women aged >40 randomly chosen from the population of Rabat with a cluster sampling method.

RESULTS

Four hundred and twenty-two healthy women older than 40 years were included in the study. The mean age was 57.2 years (8.4) [40-79] and the mean number of parities was 4.42 (2.9) [0-14]. Osteoporosis according to the classification of WHO (T-score<or=-2.5) was observed in 133 women (32.2%). The increase in the number of parities was associated to a larger body mass index and a lower BMD as well in the hips and the lumbar spine after adjustment for age. The comparison of groups of patients according to the age at menarche, the age at menopause or the period of fertility did not highlight an association with BMD. BMD at the lumbar spine and the hips was correlated negatively with age, YSM and parity and positively with BMI. Multivariate analysis showed that the determinant of BMD are BMI (OR=0.88; 95% CI: 0.83-0.92), parity (OR=1.10; 1.01-1.56) and YSM (OR=1.06; 1.03-1.10).

CONCLUSION

Bone loss in women older than 40 is a function of aging, parity and years since menopause; and there is a definite bone-protective effect of body mass weight. Further studies are required to evaluate the role of these parameters in the fracture risk.

Bone mineral density of the spine and femur in healthy Moroccan women

Bone mineral density (BMD) measurements using dual-energy X-ray absorptiometry (DXA) are widely used to diagnose osteoporosis and assess its severity. Previous studies show the necessity to establish reference data for bone mass measurements for each particular population. Such data are lacking for the Moroccan population. The aim of this study was to determine spine and femur BMD reference values for the Moroccan female population and to compare them with values from western and other Arab countries. A cross-sectional study of 569 Moroccan women, (randomly selected in the area of Rabat, the capital of Morocco, aged between 20 and 79 yr) was carried out to establish reference values of BMD. Measurements were taken at the lumbar spine and proximal femurs using DXA (Lunar Prodigy Vision, GE). The data were compared with published normative data taken by United States (U.S.), European, Kuwaiti, Lebanese, and Saudi women over 6 decades of age. The percentage of osteoporosis in postmenopausal women using our reference curve was compared to that observed when the other curves (US, European and Arab) implemented in the Lunar machine was used. Our results showed that the Moroccan women showed the expected decline in BMD at both sites with age after peaking at 20-29 years of age. Moroccan females have lower BMD at the spine than U.S., Europeans, and Kuwaitis (approximately 10-12% for patients older than 50 yr). The BMD values of the total femur in Moroccan females were close to western (European and American), and Kuwaitis, but higher than Lebanese and Saudis. Using our reference database, 37.9% of postmenopausal women had spine osteoporosis vs. 39.6% and 23.4% using US/European and Arabic Lunar reference values respectively. At the femurs, 6.7% had osteoporosis vs. 2.5% using the Arabic Lunar reference values. In conclusion, our study emphasizes the importance of using population-specific reference values for BMD measurements to avoid over or underdiagnosis of osteoporosis.